In accordance with certain aspects of the automatic protocol determination
for portable devices supporting multiple protocols, a portable device
detects which one of the multiple protocols is being used by the host
device for subsequent communication with the portable device. This
detection is based on the content of a command received from a host
device. The detected protocol is then used by the portable device for
subsequent communication with the host device. The host device may also
send, to the portable device, a notification of which of the multiple
protocols is being used by the host device.